Linear compressor

ABSTRACT

A linear compressor having a dynamic vibration-reducing unit, which is provided at a stopper, by which separation of a cylinder block is prevented, for eliminating vibration generated from a hermetically sealed container at a specific frequency band. The dynamic vibration-reducing unit comprises an elastic member disposed at the lower end of the stopper, and a mass member fixed to the bottom part of the elastic member. The elastic member is formed in the shape of a spiral plate. The elastic member is provided at the center part thereof with a through-hole, which corresponds to an opening of the stopper. The elastic member is provided symmetrically at both ends thereof with fixing parts for fixing the mass member. The mass member is formed in the shape of a plate. The mass member is provided at the center part thereof with a hollow part, which corresponds to the through-hole of the elastic member. Through the hollow part of the mass member are inserted supporting parts of the stopper frame. Both sides of the mass member are symmetrical to each other centering on the hollow part so that both ends of the mass member are fixed to the fixing parts of elastic member by means of welding or bolts.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of Korean Patent Application No. 2004-15797, filed on Mar. 9, 2004 in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a linear compressor, and, more particularly, to a linear compressor that is capable of eliminating vibration transmitted to a hermetically sealed container due to reciprocating movement of a piston, which is generated at a specific frequency band.

2. Description of the Related Art

Generally, a linear compressor is used to compress a coolant of a cooling unit, such as a refrigerator or an air conditioner. The linear compressor is provided with a linear motor, which is linearly reciprocated, as a driving unit for moving a piston forward and backward.

The linear compressor comprises: a cylinder block having a compression chamber defined therein; a piston disposed in the compression chamber of the cylinder block such that the piston is moved forward and backward; a cylinder head having an inlet chamber defined therein for introducing a coolant and an outlet chamber defined therein for discharging the coolant; and a valve unit disposed between the cylinder block and the cylinder head for controlling the introduction and discharge of the coolant.

The linear motor, as the driving unit for moving the piston forward and backward, comprises: a moving member having one side connected to the piston and the other side where a cylindrical permanent magnet surrounding the cylinder block is mounted; an inner stator fixedly disposed at the inside of the moving member; and an outer stator fixedly disposed at the outside of the moving member.

In the conventional linear compressor with the above-stated construction, there is generated a magnetic field between the outer stator and the inner stator when alternating current is supplied to the outer stator. Since the current supplied to the outer stator is the alternating current, the polarity of the magnetic field is periodically altered. Consequently, the moving member with the permanent magnet is vertically moved forward and backward. At the same time, the piston connected to the moving member is moved forward and backward in the compression chamber so that the coolant is compressed. At this time, vibration generated at a specific frequency band due to the reciprocating movement of the piston is transmitted to the hermetically sealed container, with the result that the hermetically sealed container is vibrated. Such vibration of the hermetically sealed container is a major cause of a compressor noise.

SUMMARY OF THE INVENTION

Therefore, it is an aspect of the invention to provide a linear compressor having a dynamic vibration-reducing unit for eliminating vibration generated from a hermetically sealed container at a specific frequency band.

In accordance with one aspect, the present invention provides a linear compressor comprising: a hermetically sealed container having an airtight space defined therein; a cylinder block disposed in the hermetically sealed container, the cylinder block having a compression chamber defined therein; a stopper frame fixed to the cylinder block; a stopper disposed in the hermetically sealed container for supporting the stopper frame; and a dynamic vibration-reducing unit disposed at the stopper for eliminating vibration generated from the hermetically sealed container at a specific frequency band.

Preferably, the dynamic vibration-reducing unit comprises: an elastic member fixed to the stopper; and a mass member fixed to the elastic member.

Preferably, one end of the stopper is fixed to the hermetically sealed container, and the stopper is provided at the other end thereof with an opening, through which the stopper frame is inserted, and the elastic member is provided with a through-hole, through which the stopper frame is inserted, the through-hole corresponding to the opening of the stopper.

Preferably, the elastic member is formed in the shape of a spiral plate, the through-hole being formed at the center part of the elastic member.

Preferably, the mass member is formed in the shape of a plate, and the mass member is provided with a hollow part corresponding to the opening of the stopper.

Preferably, both sides of the mass member are symmetrical to each other centering on the hollow part.

Preferably, the elastic member is integrally formed with the stopper such that the elastic member is extended from one end of the stopper.

Preferably, elastic coefficient of the elastic member and mass of the mass member are set so that a specific frequency transmitted to the hermetically sealed container and an oscillation frequency of the dynamic vibration-reducing unit correspond to each other.

BRIEF DESCRIPTION OF THE DRAWINGS

The above aspects, and other features and advantages of the present invention will become more apparent after reading the following detailed description when taken in conjunction with the drawings, in which:

FIG. 1 is a cross-sectional view illustrating the entire structure of a linear compressor according to the present invention;

FIG. 2 is a perspective view illustrating a dynamic vibration-reducing unit provided at the linear compressor according to a preferred embodiment of the present invention; and

FIG. 3 is a perspective view illustrating a dynamic vibration-reducing unit provided at the linear compressor according to another preferred embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

FIG. 1 is a cross-sectional view illustrating the entire structure of a linear compressor according to the present invention. As illustrated in FIG. 1, the linear compressor comprises: a hermetically sealed container 10 having an airtight space defined therein; a compressing unit 20 for compressing a coolant introduced thereinto and discharging the compressed coolant; and a driving unit for driving the compressing unit 20.

The compressing unit 20 comprises: a cylinder block 21 having a compression chamber 21 a where the coolant is compressed; a piston 22 disposed in the compression chamber 21 a such that the piston 22 is reciprocated; and a cylinder head 23 having an inlet chamber 23 a and an outlet chamber 23 b. Between the cylinder block 21 and the cylinder head 23 is disposed a valve unit 24 for controlling the introduction of the coolant.

The driving unit 30 comprises: a moving member 31, which is reciprocated along with the piston 22; an inner stator 32 disposed at the inside of the moving member 31; and an outer stator 33 disposed at the outside of the moving member 31. Preferably, the driving unit 30 is a liner motor.

The moving member 31 is formed in the shape of a cylinder. The moving member 31 comprises: a cylindrical part 31 a for surrounding the upper outside of the cylinder block 21; and a fixing part 31 b disposed at the same axis as a connection shaft 22 a provided at the upper end of the piston 22 so that the fixing part 31 b is vertically moved forward and backward along with the piston 22. To the cylindrical part 31 a is integrally attached a permanent magnet 31 c, which electro-magnetically cooperates with the stators 32 and 33 so that the moving member 31 is moved forward and backward.

The inner stator 32 and the outer stator 33 are disposed at the inner and outer sides of the cylindrical part 31 a of the moving member 31, respectively. The inner stator 32 is formed in the shape of a cylinder, and fixed to the outer surface of the cylinder block 21 for guiding the vertical reciprocating movement of the moving member 31 and smoothing the flow of magnetic flux through the permanent magnet 31 c of the moving member 31 from the outer stator 33. On the outer stator 33 is wound an exciting coil 33 a for moving the moving member 31 forward and backward by means of its electro-magnetic cooperation with the permanent magnet 31 c of the moving member 31. The lower end of the outer stator 33 is supported by means of a supporting part 21 b extended outward from the lower end of the cylinder block 21, and the upper end of the outer stator 33 is supported by means of an additional fixing frame 40.

On the fixing frame 40, by which the outer stator 33 is fixed, are successively disposed a plate spring 41, which is formed of a plurality of stacked plates so that the movement power of the piston is increased by means of the elasticity of the stacked plates; and a stopper frame 50 for preventing separation of the cylinder block 21. The stopper frame 50 is supported by means of a stopper 60, which is fixed to the inner upper side of the hermetically sealed container 10.

The stopper frame 50 comprises: a plurality of extension parts 51, which are extended from the fixing frame 40 in the shape of a bow; and supporting parts 52 bent from the extended ends of the extension parts 51 toward the stopper 60.

The stopper 60 is formed in the shape of a cylinder. The upper end of the stopper 60 is fixed to the inner surface of the hermetically sealed container 10. The stopper 60 is provided at the lower end thereof with an opening 61, through which the supporting parts 52 of the stopper frame 50 are inserted. The stopper 60 is provided with a dynamic vibration-reducing unit 70 for eliminating vibration generated from the hermetically sealed container at a specific frequency band. The dynamic vibration-reducing unit 70 will hereinafter be described with reference to FIG. 2.

Referring to FIG. 2, the dynamic vibration-reducing unit 70 comprises: an elastic member 80 disposed at the lower end of the stopper 60; and a mass member 90 fixed to the bottom part of the elastic member 80.

The elastic member 80 is formed in the shape of a spiral plate. The elastic member 80 is provided at the center part thereof with a through-hole 81, which corresponds to the opening 61 of the stopper 60. The supporting parts 52 of the stopper frame 50 are inserted through the through-hole 81 of the elastic member 80. The elastic member 80 is provided symmetrically at both ends thereof with fixing parts 82 for fixing the mass member 90.

The mass member 90 is formed in the shape of a plate. The mass member 90 is provided at the center part thereof with a hollow part 91, which corresponds to the opening 61 of the stopper 60. Both sides of the mass member 90 are symmetrical to each other centering on the hollow part 91 so that both ends of the mass member 90 are fixed to the fixing parts of the elastic member 80 by means of welding or bolts.

As illustrated in FIG. 3, the elastic member 80 may be integrally formed with the stopper 60 such that the elastic member 80 is extended outward from the opening 61 of the stopper 60. To the bottom part of the elastic member 80 is fixed the mass member 90 by means of welding or bolts.

Now, the operation of the linear compressor with the above-stated construction according to the present invention will be described.

When alternating current is supplied to the coil 33 a of the outer stator 33, there is generated a magnetic field between the outer stator 33 and the inner stator 32. Since the current supplied to the outer stator is alternating current, the polarity of the magnetic field is periodically altered. Consequently, the moving member 31 with the permanent magnet 31 c and the piston 22 connected to the moving member 31 are moved forward and backward in the compression chamber 21 a at the same frequency as the supplied current so that the coolant is compressed. At this time, vibration generated at a specific frequency band due to the reciprocating movement of the piston 22 is transmitted to the hermetically sealed container 10. The vibration generated at the specific frequency band is eliminated by means of the dynamic vibration-reducing unit 70 provided at the stopper 60.

Specifically, elastic coefficient of the elastic member 80 and mass of the mass member 80 are set so that the specific frequency at which the hermetically sealed container 10 is vibrated and the inherent oscillation frequency of the dynamic vibration-reducing unit 70 correspond to each other. Consequently, the mass member 80 of the dynamic vibration-reducing unit 70 is moved relative to the piston 22 while the mass member 80 has a phase opposite to the phase of the piston 22, whereby the vibration generated from the hermetically sealed container 10 at the specific frequency band is eliminated.

As apparent from the above description, the present invention provides a linear compressor having a dynamic vibration-reducing unit disposed at a stopper, which is provided for preventing separation of a cylinder block. The dynamic vibration-reducing unit comprises an elastic member and a mass member.

Consequently, vibration transmitted to a hermetically sealed container due to the reciprocating movement of a piston, which is generated at a specific frequency band, is eliminated by means of the mass member, which is moved relative to the piston while the mass member has a phase opposite to the phase of the piston, whereby the compressor is operated quietly.

Furthermore, the dynamic vibration-reducing unit is integrally formed with the stopper, whereby the number of parts of the linear compressor is reduced, and spatial applicability of the inside of the compressor is improved.

Although the preferred embodiments of the invention have been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims. 

1. A linear compressor comprising: a hermetically sealed container having an airtight space defined therein; a cylinder block disposed in the hermetically sealed container, the cylinder block having a compression chamber defined therein; a stopper frame fixed to the cylinder block; a stopper disposed in the hermetically sealed container for supporting the stopper frame; and a dynamic vibration-reducing unit disposed at the stopper for eliminating vibration generated from the hermetically sealed container at a specific frequency band.
 2. The compressor according to claim 1, wherein the dynamic vibration-reducing unit comprises: an elastic member fixed to the stopper; and a mass member fixed to the elastic member.
 3. The compressor according to claim 2, wherein one end of the stopper is fixed to the hermetically sealed container, and the stopper is provided at the other end thereof with an opening, through which the stopper frame is inserted, and wherein the elastic member is provided with a through-hole, through which the stopper frame is inserted, the through-hole corresponding to the opening of the stopper.
 4. The compressor according to claim 3, wherein the elastic member is formed in the shape of a spiral plate, the through-hole being formed at the center part of the elastic member.
 5. The compressor according to claim 2, wherein the mass member is formed in the shape of a plate, and the mass member is provided with a hollow part corresponding to the opening of the stopper.
 6. The compressor according to claim 5, wherein both sides of the mass member are symmetrical to each other centering on the hollow part.
 7. The compressor according to claim 2, wherein the elastic member is integrally formed with the stopper such that the elastic member is extended from one end of the stopper.
 8. The compressor according to claim 2, wherein elastic coefficient of the elastic member and mass of the mass member are set so that a specific frequency transmitted to the hermetically sealed container and an oscillation frequency of the dynamic vibration-reducing unit correspond to each other. 